I'm trying to make a web based media player using the HTML5 audio element implemented in Firefox 3.5 and Chrome. Reading Mozillas documentation, omitting the autobuffer attribute should result in the audio src not being requested:

if specified, the audio will
automatically begin being downloaded,
even if not set to automatically play.
This continues until the media cache
is full, or the entire audio file has
been downloaded, whichever comes first

However, on the server side I notice the files are being requested anyway. My sample page is very simple:

According to the article "Configuring Servers for Ogg Media", Ogg media does not contain duration information, so to correctly display a slider you need to include an X-Content-Duration header. If you don't include such a header, Firefox will prefetch portions of the media* so that it can work out the duration and display a slider.

That could be your problem.

* It will fetch the first few bites, which should give it a Content-Length header so it knows the file size. It will then use that file size to fetch the last few bites, from which it can work out the duration. If your server does not support Range requests, the result will be that it'll fetch the whole file.